A component mounting line is provided with a screen printer which prints a paste such as solder on a substrate and a component mounting machine which mounts a component on the substrate on which the paste is printed by the screen printer. In the screen printer of such a component mounting line, a substrate clamped at the sides thereof by a pair of clamping members is brought into contact with a lower surface of a mask having pattern holes formed thereon, a squeegee is slid on the mask contacting with the substrate to fill the pattern holes of the mask with the paste, and then the substrate is moved in a direction away from the mask to perform plate releasing.
In such a screen printer, the thickness of a mask has been reduced owing to formation of a fine printing pattern associated with formation of a fine-pitch substrate in recent years. When the thickness of the mask is reduced as described above, the mask brought into close contact with a substrate upon filling of a paste by a squeegee is pulled toward the substrate in the subsequent plate releasing and a central portion of the mask is thus bent downward. Thus, directions of plate separation in end portions of the substrate may not be perpendicular to the substrate, and thus shapes of the paste after printing may collapse and printing accuracy may be deteriorated. Therefore, a technique has been known in which a suction mechanism which vacuum-sucks a substrate to a lower receiving portion which supports the substrate from below is provided, and in plate releasing, without moving down a clamping mechanism, only the lower receiving portion vacuum-sucking the substrate is moved down so that a mask is not pulled toward the substrate and not bent downward in the plate releasing (see Patent Document 1, for instance).
Patent Document 1 is JP-A-H7-214748.